<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    [v-cloak] {
      display: none;
    }
  </style>
</head>
<body>
  <div id="app">
    <!-- <p v-pre>{{msg}}</p> -->
    <!-- <p v-once>{{msg}}</p> -->
    <!-- <button @click="msg=1234">改变</button> -->
    <p v-cloak>{{msg}}</p>
  </div>
  <script src="https://cdn.jsdelivr.net/npm/vue@2.6.14/dist/vue.js"></script>
  <script>
    let vm  = new Vue({
      el: "#app",
      data: {
        msg: 'hello'
      }
    })
  </script>
</body>
</html>